(a) Field of the Invention
The present invention relates to a fabric for tents and a process for preparing the same, particularly to a fabric consisting of a gray woven from nylon or polyester filaments and a layer of coating composition including polyurethane as a main component and an additional pigment, an ultraviolet inhibitor, aluminum powders, ceramic powders, a fire retardant agent and a solvent. The fabric can be protected from a yellowing appearance caused by ultraviolet rays and has a preferable color. The lifetime of the fabric can be extended. The process for preparing the fabric can be carried out at comparative low cost and short time periods.
(b) Description of the Related Art
Nowadays, demand for tents is increasing continuously because camping, hiking, etc. are becoming more widespread as leisure activities or outdoor sports. Additionally, the fabrics for tents are used widely for various events. It is desirable that fabric used in tents be resistant to water, fire, and ultraviolet sunlight. In the aspects of dyeing properties, cost and physical strength, fabrics prepared with nylon grays represent the main portion of fabrics for tents. Fabrics prepared with polyester and cotton grays are used in comparatively smaller amounts.
Compared with FIGS. 2 and 4, a general process for preparing a fabric for tents prepared with nylon grays is described below.
A gray is prepared from nylon filaments through a sizing process. It will be understood that as used herein, the term "gray" refers to an unfinished fabric just off of a loom or knitting machine, and that the spellings "greige" and "grey" are also used in this art with the same meaning. After the sizing process, the gray is scoured from sizing agents and other contaminants through a scouring process, and dyed in a dyeing process. The dyeing process for dyeing the fabric for tents is a lengthy process requiring approximately 18 hours. Furthermore, the dyeing process contaminates water used in the washing process. Because of factors such as ultraviolet resistance, shrinkage, heat resistance, etc., nylon has been widely used for grays because nylon has superior dyeing properties to polyester. For example, a nylon gray can be dyed through a low temperature dyeing process performed at below 100.degree. C., but a polyester gray has to be dyed through a high temperature dyeing process performed at above 120.degree. C. or through a carrier dyeing process. Therefore, cost of dyeing polyester gray is typically higher than the cost of dyeing nylon. The dyed gray is dried and stretched through a tentering process to prepare a primary fabric (21) for tents.
To provide waterproof, fire retardant and ultraviolet inhibiting properties, a polyurethane coating layer (22) is coated on a surface of the primary fabric. The surface having the above coating layer faces to the interior of a tent. Usually, this coating layer is formed by a knife coating method with the presence of polyurethane, toluene (as a solvent), an ultraviolet inhibitor, a fire retardant agent and a water repellent agent. Thereafter, a water repellent (W/R) coating layer (23) is coated on the other surface of the fabric. The surface having the W/R coating layer is the opposing surface having the polyurethane coating layer. The W/R coating layer prevents the nylon primary fabric from hanging down during a rainy or snowy time.
The conventional fabrics for tents prepared with the above processes become discolored (i.e., yellow appearance) when exposed to ultraviolet rays for comparatively short time. The conventional fabrics have problems of color defects and have short lifetime. Moreover, the high cost and much time are necessary for the processes for preparing the conventional fabrics because of the dyeing process.